They could adjust an Inheritance for Each avatar instead of a flat "JT" transaction. for instance
1) You Gain a stat boost related to the Avatars Element
*Example: Ifrit=STR+30, Titan=VIT+30, etc
2) You gain a strong Enspell Effect related to Avatars Element
3) A Unique buff is gained based on the Avatar
4) A Unique aura is gained based on the avatar.
5) Combat skills are enhanced.
6) Defenses are enhanced
7) Access to a Unique Staff WS based on Avatar
Sounds like a lot, But we lose our Avatars... So it seems like a fair trade off? Maybe...,
If you've read this far bravo, I do have to say this idea does sound a bit ludicrous... But i've always like the idea of Becoming the Avatar, or infusing your avatars power into you to augment your combat capabilities. That being said i think its a bit unrealistic in FFXI.
It wouldn't fit right and SMN was never meant to be frontline, While i think something like this would be really really fun. I just do not see it being realistic
